Silver halide emulsions containing chain-substituted cyanine dyes



United States Patent U.S. Cl. 96-106 8 Claims ABSTRACT OF THE DISCLOSURESilver halide emulsions containing at least one of the wherein R and Rare alkyl groups, Y is selected from the class consisting of oxygen andsulphur, Z is a saturated alkylene group containing up to 6 carbon atomsin the chain, each of x, y and z are selected from O and 1, and D and Dare each the residue of a heterocyclic nucleus selected from the groupconsisting of thiazoles, oxazoles, selenazoles and their polycyclichomologues of the benzene and naphthalene series, pyridine and itspolycyclic homologues, indolenines, diazoles, thiazolines and diazines.

This invention relates to cyanine dyestufis, to their production and tophotographic silver halide emulsions containing the said dyestufis asoptical sensitising agents.

According to the present invention there are provided dyestuffs of thegeneral Formula I:

where R and R are alkyl groups. Y is an oxygen or sulphur atom, Z is asaturated alkylene group containing up to 6 carbon atoms in the chain,x, y and z are the same or different and are each nought or one, and Dand D, are each the residue of a five-membered or six-mcmberedheterocyclic nucleus.

In the foregoing formula R and R are preferably methyl, ethyl, propyl orbutyl groups but may be higher alkyl groups.

D and D may each be the residue of any five-membered or six-memberedheterocyclic ring system including thiazoles, oxazoles, selenazoles andtheir polycyclic honrologues such as those of the benzene andnaphthalene series; pyridine and its polycyclic homologues, such asquinoline and uand B-naphthoquinolines; indolenines; diazoles (e.g.1:3:4-thiadiazole); thiazolines; diazines (e.g., pyrimidines andquinazolines). The polycyclic compounds of the series may be substitutedin the carbocyclic rings with one or more groups such as alkyl, aryl,alkoxy and methylene dioxy groups, or by halogen atoms.

According to a further feature of the present invention there isprovided a process for the production of a dye- 3,460,947 Patented Aug.12, 1969 stuli of general Formula I which comprises reacting a compoundof the general Formula II:

or the corresponding zwitterion of the general Formula III:

assigned to them above, with a compound of the general Formula IV:

where Q is an alkylthio, alkylthiovinyl or acetanilidovinyl group andthe other symbols have the meanings assigned to them above. X may be anyacid radical, for example halide (chloride, bromide, iodide), sulphate,sulphamate, perchlorate or p-toluene sulphonate.

The process is preferably carried out by heating the reagents togetherin the presence of a basic condensing agent, e.g., an inorganic basicagent such as sodium acetate, or an organic agent such as pyridine ortriethylarnine.

An alternative process for the production of dyes of Formula I where Yis sulphur comprises reacting a compound of the Formula V:

X IV

Ri V

with a sultone of the Formula VI:

or with a halo-alkane-sulphonic acid of the Formula VII Hal-Z-SOaH VIIwhere the symbols have the meaning assigned to them above and Hal is ahalogen atom.

The dyestuffs differ from dyestuffs known in the art fundamentally inthe presence of the sulphonic acid residue. They have been found to bevery strong sensitisers for photographic silver halide emulsions,including silver bromide, chloride, chlorobromide and iodobromideemulsions. For this purpose they are used in the same manner and amountas cy-anine sensitising dyes known per se. The invention accordinglyincludes such emulsions, particularly gelatino silver halidephotographic emulsions, containing one or more of the dyestuffs ofgeneral Formula I in sensitizing amount.

The following examples will serve to illustrate the invention:

EXAMPLE 1 Anhydro-bis-(3-ethyl-2-benzothiazole)B-3-sulphopropoxytrimethincyanine hydroxide A mixture of2-acetylmethylene-3-ethylbenz0thiazoline (1.1 g.) and 1,3-propanesultone(0.6 ml.) was heated at Anhydro (3 ethyl 2 benzothiazole)(5,6-dimethoxy-3- methyl 2 benzothiazole) ,3 3sulphopropoxytrimethincyanine hydroxide The method of Example 1 wasfollowed, but using 5,6- dimethoxy-3-methyl 2 methylthiobenzothiazoliumtoluene-p-sulphonate. The dye formed red needles, M.P. 206- 207.

The dye extends the sensitivity of a silver iodobromide photographicemulsion to 6200 A. with a maximum at 5,950 A.

EXAMPLE 3 Anhydro-(3-ethyl-2-benzothiazole) (1-ethyl-2-quinoline)3-3-sulphopropoxy-trimethincyanine hydroxide The method of Example 1 wasused, but with 1-ethyl-2- methylthio-quinolinium toluene-p-sulphonate(1.9 g.) The dye was obtained as bronze-coloured crystals, M.P. 179-181, by crystallization from ethanol.

The dye extends the sensitivity of a silver iodobromide photographicemulsion to 6000 A., with a maximum at 5,750 A.

EXAMPLE 4 Anhydro-bis-(3-ethyl-2-benzothiazole)-,6-3-sulphopropylthi'otrimethincyanine hydroxide A mixture of1,3-bis-(3-ethyl-2-benzothiazolinylidene)- propan-Z-thione (0.5 g.),1,3-propanesultone (1.0 ml.) and chloroform (10 ml.) was refluxed for 1/2 hours. The tar remaining on evaporation of the solvent was dissolvedin methanol, and the solution was treated with dilute aqueous ammonia.The solid which separated was collected, washed with cold water and hotbenzene, and crystallised from ethanol to give the dye, M.P. 195-197".

EXAMPLE 5 Anhydro-bis-(3-ethyl-2-benzothiazole)fl-3-sulphopropoxypeutamethincyanine hydroxide2-Acetylmethylene-3-ethylbenzothiazoline (1.1 g.) was quaternised with1,3-propanesultone (0.6 g.) as in Example l. The product and3-ethyl-2-w-ethylthiovinylbenzothiazolium iodide (1.9 g.) were refluxedtogether in ethanol ml.) containing triethylamine (1.0 ml.) for 30minutes. The solid which separated was collected, washed with coldethanol, and crystallised from methanol. The dye was obtained as deepblue needles, M.P. 202-203".

The dye imparts a new band of sensitivity to a silver iodobromidephotographic emulsion from 6,200 to 6,750 A., with a maximum at 6,600 A.

Using the method of Example 1, the following Examples 6 to 8 wereobtained from 2-acetylmethylene-3- ethylbenzothiazoline:

EXAMPLE 6 Anhydro (3-ethyl-2-benzothiazole) (5-methoxy-3-methyl- 2benzothiazole) 13-3-sulphopropoxytrimethincyanine hydroxide The dyeformed red needles, M.P. 210 (decomp.), after boiling out with methanol.

The dye extends the sensitivity of a silver iodiobromide photographicemulsion to 5,700 A., with a maximum at 5,250 A.

4 EXAMPLE 7 Anhydro (3 ethyl 2 benzothiazole)(5 chloro 3- methyl 2benzothiazole) 8 3 sulphopropoxytrimethincyanine hydroxide The dyeformed red crystals, M.P. 185-186 (decomp.), after crystallization frommethanol.

The dye extends the sensitivity of a silver iodobromide photographicemulsion to 5,650 A., with a maximum at 5,300 A.

EXAMPLE 8 Anhydro (3 ethyl 2 benzothiazole) (3-ethyl-5,6-dimethoxy 2benzothiazole) ,6 3 sulphopropoxytrimethincyanine hydroxide The dye wasobtained as red crystals, M.P. 176 (decomp.) by crystallization fromethanol.

The dye extends the sensitivity of a silver iodobromide photographicemulsion to 5,850 A., with a maximum at EXAMPLE 9 Anhydro (3 ethyl 5methyl 2 benzoselenazole) (5,6 dimethoxy 3 methyl 2 benzothiazole) [3 3-sulphopropoxytri-methincyanine hydroxide A mixture of2-acetylmethylene-3-ethyl-5-methylbenzoselenazoline (1.4 g.) and1,3-propanesultone (0.7 g.) was heated at for 15 minutes.

The product and 5,6-dimeth0xy-3-methyl-2-methylthiobenzothiazoliump-toluenesulphonate (2.2 g.) were refluxed together in ethanol (10 ml.)containing triethylamine 1.4 ml.) for 30 minutes. The resulting solutionwas treated with a little dilute aqueous ammonia, and the solid whichseparated was filtered off and washed with water and benzene.Crystallization from methanol gave the dye as purple crystals, M.P.257259 (decomp).

EXAMPLE 10 Anhydro (3 ethyl 2 benzothiazole) (1 methyl 2-naphtho(1,2d)thiazole) B 3 sulphopropoxytrimethincyanine hydroxide2-Acetylmethylene-3-ethylbenzothiazoline (2.2 g.) was reacted with1,3-propanesultone as in Example 1. The product was refluxed in ethanol(20 ml.) with l-methyl- 2 methylthi'onaphtho[l,2d]thiazoliump-toluenesulphonate (prepared by heating Z-methylthio-fl-naphthothiazole(2.3 g.) and methyl p-toluenesulphonate (1.9 g.) at 165 for 2 hours) andtriethylamine (2.8 ml.). After 1 hour the solution was cooled andtreated with dilute aqueous ammonia. The solid which separated wascollected and washed successively with water, ether and ethanol. Afterboiling out with methanol the dye was obtained as red crystals, M.P.216-218".

EXAMPLE 1 1 Anhydro (3 ethyl 2 benzothiazole) (3 methyl 5- phenyl 2benzoxazole) ,8 3 sulphopropoxytrimethincyanine hydroxide A mixture of.2-acetylmethylene-3-ethylbenzothiazoline (1.1 g.) and 1,3-propanesultone(3.5 g.) was heated at for 1 hour.3-Methyl-5-phenyl-2-benzoxazolinethione (1.8 g.) was added and heatingat the same temperature was continued for a further 2 hours.

Pyridine was added to the melt, and the mixture was refluxed for 15minutes. The solution was cooled and diluted with water, and the solidwas filtered 01f, washed with water and benzene, and boiled out withmethanol. The dye formed red crystals, M.P. 235237.

EXAMPLE 12 Anhydro (3 ethyl 2 benzothiazole) (5,6 dimethoxy-3-methyl-2-benzothiazole) ,B-3-sulphopropylthiotrimethincyaninehydroxide A mixture of 3-ethyl-2-thioacetylmethylenebenzothiazoline(2.35 g.) and 1,3-propanesultone (1.4 g.) was heated at 100 for 30minutes. The resulting quaternary salt was refluxed in ethanol (20 ml.)with 5,6-dirnethoxy-3-methyl- Z-methylthiobenzothiazoliump-toluenesulphonate (5.3 g.) and triethylamine (2.8 ml.). After 30minutes the solution was cooled and treated with dilute aqueous ammonia.The tar which separated was washed with water, and then stirred withaceton, when it hardened. The dye was crystallized from ethanol, when itformed deep blue crystals, lVLP. 261-263".

EXAMPLE 13 Anhydro (3 ethyl 2 benzothiazole) (5 chloro 3- methyl 2benzothiazole) ,8 4 sulphobutylthiotrimethincyanine hydroxide A mixtureof 3-ethyl-2-thioacetylmethylenehenzothiazoline (2.35 g.) and1,4-butanesultone (2.0 ml.) Was heated at 150 for 40 minutes. Theproduct and 5-chloro- 3 methyl 2 methylthiobenzothiazolium ptoluenesulphonate (4.1 g.) were refluxed in ethanol (20 ml.) withtriethylamine (2.8 ml.) for 30 minutes. Addition of dilute aqueousammonia to the solution caused the separation of a tar, which washardened by washing with water and then acetone. Crystallization fromethanol yielded the dye as green crystals, M.P. 190-192".

EXAMPLE 14 Anhydro bis (3 ethyl 2 benzothiazole) B 2sulphoethylthiotrimethincyanine hydroxide wherein R and R are alkylgroups, Y is selected from the class consisting of oxygen and sulphur, Zis a saturated alkylene group containing up to 6 carbon atoms in thechain, each of x, y, and z are selected from 0 and 1, and D and D areeach the residue of a heterocyclic nucleus selected from the groupconsisting of thiazoles, selenazoles and their polycyclic homologues ofthe benzene and naphthalene series, pyridine and its polycyclichomologues, indolenines, diazoles, thiazolines and diazines.

2. The silver halide photographic emulsion of claim 1 wherein R and Rare each selected from the group consisting of methyl, ethyl, propyl andbutyl.

3. The silver halide photographic emulsion of claim 1 wherein saiddyestuif. is anhydro(3-ethyl-2-benzothiazole)(5,6-dimethoxy-3-methyl-2-benzothiazole) ,8 3sulphopropoxytrimethincyanine hydroxide.

4. The silver halide photographic emulsion of claim 1 wherein saiddyestuff is anhydro-(3-ethyl-2-benzthiazole) (3 ethyl-5,6dimethoxy-Z-benzothiazole) 13 3 sulphopropoxytrimethincyanine hydroxide.

5. The silver halide photographic emulsion of claim 1 wherein saiddyestuif is anhydro-(3 ethyl 5 methyl 2- benzoselenazole) (5,6 dimethoxy3 methyl 2 benzothiazole) fl-3-sulphopropoxytrimethincyanine hydroxide.

6. The silver halide photographic emulsion of claim 1 wherein saiddyestufi is anhydro-(3-ethyl-2-benzothiazole) (1-methyL2-naphtho (1,2d)thiazole)fi3-sulphopropoxytrirnethincyanine hydroxide.

7. The silver halide photographic emulsion of claim 1 wherein saiddyestufi is anhydro-(3-ethyl-2-benzothiazole) (5,6dimethoxy-3-methyl-2-benzothiazole) B 3 sulphopropylthiotrimethincyaninehydroxide.

8. The silver halide photographic emulsion of claim 1 wherein the silverhalide is silver iodobromide.

References Cited UNITED STATES PATENTS 2,503,776 4/1950 Sprague 961063,148,187 9/1964 Haseltine 96106 3,352,857 11/1967 Brooker et al. 961063,403,149 9/ 1968 Picker 96--106 J. TRAVIS BROWN, Primary Examiner US.Cl. X.R. 260240

